Sanding machine



June 25, 1940. l 2,205,492

SANDING MACHINE Filed Dec. 27, 1957 3 Sheets-Sheet l A TTORNEY.

SANDING MACHINE June 25, 1940.

3 Sheets-Sheet 3 Fil ed Dec. 27, 1957 IN VEN TOR.

RAYMOND A. REID ATTORNEY Patented June 25, 1940 v SANDING MACHINE,

Raymond A. Reid, Cedar-Rapids, Iowa- I Application December 27, 1937, Serial No. 1 81,'7 5l3' I 15 Claims. (or 51-174) This invention relates to floor sanding devices and has'particular relation to a device suitable for sanding, finishing and'polishing flat surfaces such as floors and the like.

A general object of my invention isto provide a power driven device for sanding, scraping, polto provide, in a machine of the above character,

means for causing the work-engaging member of V the machine to movewith an eccentric or elliptical movement.

Another object of my invention is to provide,

in a device of the above character, counterbalancing or counter-poise forces for minimizing vibration in the'machine. 7

Another object of my invention is to provide means for materially reducing the wear of the working parts of a device of the above character.

Another object of my invention is to provide readily interchangeable work-engaging means.

Other and further features and objects of the invention will be moreapparent to those skilled in the art upon a consideration of the accompanying drawings and following specifications, wherein is disclosed a single exemplary embodiment of the invention, with the understanding, however, that such changes may be made therein as fall within the scope of the appended claims, without departing from the spirit of the invention.

In said drawings:

Figure 1 is a view in perspective of a device constructed according to one embodiment of my invention.

Figure 2 is a fragmentary view in perspective of the under side of the device shown in Figure 1.

Figure 3 is a fragmentary view in perspective of the operating parts of the device shown in Figure 1. 1

Figure 4 is a view in elevation of the handle of the device. shown in Figure 1.

Figure 5 is a view in perspective of the workengaging pad ofthe device shown in Figure 1.

, Figure 6 is a view in perspective of the weight used in applying pressure to the sanding device.

Figure '7 is a view in perspective of the frame and pad of the sander.

Figure 8 is a view in perspective of the motor for driving the mechanism of the sander, and

Figure 9 is a schematic diagram to illustrate in exaggerated relation the motion which takes switch l2b on top of the motor is employed for place in a device constructed according to one embodiment'of my invention. g j I Referring now tov the drawinga'a device constructed acocrding to one embodiment of my invention includes a base l0,.a sanding block ll, 5 a motor l2, a linkage, indicated generally at 13, for driving the sandingblock ,irom the motor, a handle it for propelling and guiding themachine over the floor or other surface to be treated, and for. furnishing a counter-racting lever arm or vibration damping means for the machince, and a weight It for applying pressure to the sanding block.

The base, shown more particularly in Figure 7, is roughlyrectangular in shape and is provided with a raisedplatform Illa at one end of the upper face thereof to act as a supporting means for the weight I6 and as a means for securing the pad I l to the machine, as will hereinafter .more particularly appear. The face Ina is provided with a boss lob threaded on the inner wall thereof as indicated at lflc. An intermediate portion of the base I0 is provided with oppositely-disposed, upwardly-projecting lugs Ind and ille to which the arms of the handle It may be attached. The upper face of the base is also provided with a cylindrical cup shown at Ill for the reception of the motor I2. I l

The motor I2 is, of course, only one example of a driving means, and any other suitable driving means might be employed. The motor is preferably adapted for operation in a vertical axis and electrical current is conducted to the motor by means of conductors indicated at no. The

8B turning the current on and off. The shaft of the motor, indicated at 120, is threaded, as indicated at [2d, in order that it may be threaded into the threaded hole Ila. of the eccentric indicated generally at. H. The lock nut He is employed for locking theshaft in place in the eccentric "b.

The shaft I20 extends below the lower face of the member He and an anti-friction bearing, such as the bearing 20, is mounted on the shaft. The. eccentric bearing 20 is received in a cup 25 which 45 in turn is a part of a. cross member I02 of base Ill. The eccentric-lib thus acts as a cam, the bearings of which are provided by the cup 25, the bearing 20 and the bearings of the motor. In other words, the eccentric ,llb acts as the cross pin of a crank and the, motor bearings and cup 25 act as the bearings for the crank shaft.

The motor here shown preferably rotates at approximately 1750 R. P. M., but of course motors with other operating speeds may be employed.

An anti-friction bearing is employed in conjunction with the eccentric ilb and the inner-race "c is a wedge flt on the eccentric iib, while the outer race I 1d is received in a cup-like clamping member llc, the clamping member being adapted to be tightly engaged to theouter race i1d by means of the ears i1! and locking screw Ila. The eccentric i1 is provided with a flange ilh on the opposite side of the cup-like member lle and a wide strip of flexible material such as spring steel indicated at ilais riveted, or otherwise secured to the under side of the flange "h. The opposite end of the strip or link Ila is riveted toa flange iia which is a part of the padplateii.

Itistobenotedthat thelinkila maybe freely flexed in a direction vertical to the plane of rotation of the eccentric ll,- but readily transmits turning and reciprocating motions from the eccentric to the sanding pad. The sanding pad may thus move freely up and down as pressure is applied to it without placing any bending moments on the eccentric to cause binding, injury, or wear on themcentric.

The interior of the base ll is hollow as indicated at II and the means for holding the sanding pad in place beneath the base includes the channel-shaped resilient members it and If. These members may be of any suitable resilient material or any suitable shape.

A preferred means of securing the channel members I! and 2| to the base II and to the pad plate i i include the oppositely disposed plates 22 and 2!. These plates are located within the box-like figure formed by the opposed channels it and 2i, and they extend across the adjacent edges of the channels as illustrated. Screws 2! pass through the raised platform ill; and have threaded engagement with the upper plate 22 and when these screws are drawn tight the plate will securely rip the upper flanges of the resilient members iland'zl. In the same manner screws 20 project through the bottom of the pad plate ii and have threaded engagement with the lower plate 23, and when these screws are tightened the lower flanges of 'the resilient members is and 2| are tightly engaged to the pad plate ii. The edgesof the padplate ii areturnedup, as indicated at lib, for assisting to confine the resilient members I! and 2| and likewise these edges are provided with downwardly projecting flanges iic adapted to be received in the grooves 210 of the pad 21 to hold the sheet of sand paper, or the like, indicated at 22, in place. The pad plate ii is provided with upwardly projecting ears lid and these ears have threaded bosses lie for the reception of set screws 2! adapted to hold the pad 21 in place on the pad plate ii.

The pad 21 is preferably provided with a layer of resilient material, such as sponge rubber, as indicated at ii, on the lower face thereof. 0!

course any desired material such as emery cloth,

sand paper, cotton cloth or the like may be substituted for the sand paper 2! in accordance with the use to which the machine is to be put. It will be found that a pad of cloth, steel wool or like material may be placed on the floor beneath the pad 21 and, with no other fastening but the friction of the sand paper 22 on the material, the material will be moved by the pad to abrade or polish the floor as desired. This feature makes it very easy to sand the floor and to then polish it without making any adjustment of the machine.

I have found it desirable, in using the machine, to employ a weight, such as indicated at II, and this weight isrecessed, as indicated at a, to flt closely around the motor i2 and circular flange III. It is preferably rounded, as indicated at lib, for the sake of appearance. The weight I. is preferably provided with a combined carrying means and locking means illustrated at 82, and this locking means consists of the handle 32a which is received, on a bolt 82!). The belt 82b is threaded at its lower end, as indicated at 32c, and this threaded portion is received in a recess lOc extending from the lower face of the weight II. A washer-like member 32d is provided on the lower end of the bolt above the thread 82c and within the recess lie, so that the handle its may be employed to carry the weight, the washer 32d acting to prevent the handle 32 from being withdrawn from the weight. The threads I2c-of the bolt 22!: may be threaded into the threaded boss llb to lock the weight on the base. It will be found that this weight serves two purposes, one in applying pressure to the sanding block 21 and also in minimizing vibration of the machine.

Vibrationis, of course, present to a greater or less degree in all reciprocating machines, and this condition is, of course, undesirable in a portable machine of this. character. Although vibration might be substantialLv eliminated by adding suflicient weight to the machine, it is, of course, impractical to do this with a portable machine of the character of the present device. It has even been proposed to use oppositely re-. ciprocating blocks to overcome vibration, but this entails superfluous and unnecessary mechanism. 35

The inertia of the weight ll is effective to a limited degree to reduce vibration of the machine, but practical considerations make it undesirable to utilize this method of reducing vibration to a point where the machine is entirely free or substantially free of undesirable vibration.

I have devised a unique means for further reducing and minimizing undesirable vibration of the machine as a whole. This is accomplished by means of the handle it. In order to secure a counter-balancing force reaction which will act against the direction of vibration of the base, I provide a locking means such as the turn-buckle 34 adapted to draw the side members Ila and lib of the handle ll together to cause them to engage the weight I and motor i2 at the sides thereof to definitely lock the handle with respect to the base. It will be found that-the handle ll now acts-as a counter-weight or counter-poise which, apparently because of the long lever arm of the handle, sets up a counter-vibration which minimizes the vibration of the machine as a whole. I may carry this counter-action or damping effect to completion by applying an additional weight, indicated at 30, to the upper end of the handle it.

I preferably provide depending lug members ilq beneath the collar iii! and these lugs are drilled as indicated at ilh to receive a shaft 21 on which rollers or casters 38 are mounted. These rollers permit the machine to be readily moved about by tilting downwardly on the handle it to raise the pad 21 from the floor.

In operation of a'device constructed according to my invention, it will be found that the pad 21 will move not only with an oscillatory or reciprocatory movement but also with a circular movement, so that portions on the pad will move in the path of an ellipse, thus providing not only a reciprocatory movement of the pad, but also a rotary motion, the. combination of movements die and a weight in the handle extending above being particularly eifectlvein the sanding and polishing operations for which the machine is intended. I havev attempted to illustrate these movements in exaggerated relation in Figure 9.

As the eccentric lib rotates, the pad'plate II I and padv 21 will be pushed from-backto front and pulled from front to back. As' the pad first starts to move from front to back, for instance, the] eccentric isymoving; outwardly from the center line from the axis of rotation of the eccen- I tric to the center of the pad and the entire pad will be rotated substantially about a vertical axis passing through the center of the pad (position A). As further outward and rotary movement of the eccentric occurs, the front to back movement of the pad begins, and as the eccentric further revolves through 180 degrees, the pad is pulled to the opposite side .(position B) and is then rotated in the opposite direction on a vertical axis passing through the pad (position C). As rotation of the eccentric is continued through 360 degrees, the pad is moved in the opposite direction to complete the cycle of movement.

Although I have described a specific embodiment of my invention, it is apparent that modifications thereof may be made by those skilled in the art, without departing from the spirit and scope of my invention, as set'forth in the appended claims.

I claim as my invention:

1. In a sanding machine, a base, an eccentric rotatably mounted with respect to the base, a pad resiliently mounted on the base by means of flexible channeled members and spaced from the eccentric, and a spring like link for connecting the pad with the eccentric flexible in a vertical direction to permit up and down movement of the pad with reference to the eccentric and stiff in the horizontal plane to transmit reciprocating movement from the eccentric to the pad.

2. In a sanding machine, a base, an eccentric rotatably mounted with respect to the base, means for driving the eccentric, a pad, resilient channeled member means for flexibly mounting the pad on the base, and a link for connecting the pad with the eccentric, the link being flexible in one direction only.

3. In a sanding machine, a base, a pad mounted for reciprocating movement with respect to the base, means for reciprocating the pad, means for damping the vibration of the base comprising a weight, and handle means for removably securing the weight to the base.

4. In a sanding machine, a base, a pad mounted for reciprocating movement with respect to the base, means for reciprocating the pad, means for damping the vibration of the base comprising a weight, and means for removably securing the weight to the base, the said means for securing the weight to the base including a carrying handle for engaging the weight to the base and for carrying the weight.

5. In a sanding machine, a base, a pad mounted for reciprocation with respect to the base, means for driving the pad with a reciprocating movement, and counter-poise means comprising a handle and a weight removably fixed to the base by the handle and extending above the base in a direction outside the plane of vibration of the base.

6. In a sanding machine, a base, a reciprocating mechanism mounted on the base for sanding a floor, and a counter-poise comprising a hanthe base and removably secured to the base by meanso! the handle.

1 v'1. :Ina machine, a base, reciprocating sanding means mounted on thebase, means for damping the vibration of the base comprising a counter-poise including a weight extending above the base, and a handle extending therethrough to the base to removably flxthe weight' to the :base and to carry the weight. I

8. In a sanding machine,- a substantially rec ,tangular hollow base, resilient plate means engaged within thebottom of the base and extends ing therebelow, apad mounted on the plate means, a motor mounted on'the upper face of the base in spaced relation to the pad, a cross bar beneath the motor, an eccentric mountedfor rotation in the cross bar and on the motor shaft, and a flexible link connecting the eccentri and the pad.

9. In a sanding machine, a base, resilient channel members mounted beneath the base and secured thereto, a sanding pad mounted on the lower edges of the channel members, an eccentric mounted in the base for rotation with respect thereto, a motor for driving the eccentric, a resilient link means connecting the eccentric and the pad, and a weight removably secured to the base by a handle,

10. In a sanding machine, a base, resilient channel members mounted beneath the base and secured thereto, a sanding pad mounted on the lower edges of the channel members, an eccentric mounted in the base for rotation with respect thereto, a motor for driving the eccentric, and a resilient link means connecting the eccentric and the pad, the resilient link being flexible in a vertical direction and stifi in the horizontal direction.

11. In a sanding machine, a base, a pad, resilient channel member means for mounting the pad on the base for twisting movement about a vertical axis and reciprocatory movement in a horizontal plane, a drive means for moving the pad including an eccentric mounted on the base for rotation in a horizontal plane, and a link flexible in a vertical plane but stiff in a horizontal plane whereby rotating movement of the eccentric is transferred by the link to the pad to cause twisting and reciprocating movement of the pad in a horizontal plane.

12. In a sanding machine, a base, a pad, resilient flexible channel members for mounting the pad on the base for twisting movement about a vertical axis and a reciprocatory movement in a horizontal plane and for limited vertical movement as a whole, a drive means for moving the pad including an eccentric mounted on the base for rotation in a horizontal plane, and a link flexible in a vertical plane but still in a horizontal plane whereby rotating movement of the eccentric is transferred by the link to cause twisting and reciprocating movement of the pad in a horizontal plane and to permit limited vertical movement of the pad to adjust its vertical position with reference to the base.

13. In a sanding machine, a base, a pair of resilient flexible channel members positioned with the edges of the flanges'thereof adjacent each other and spaced from each other, a plate within the channel members and bearing against the under sides of the upper flanges, means for drawing the plate against the under side of the base to thus grip the upper flanges on the base, a sanding pad including a sanding pad plate on the lower faces of the lower flanges. a plate on the upper faces of the lower flanges. meana for drawing the plate down. against the landing pad plate, and means for applying twisting and reciprocating motion to the sanding pad.

. 14. In a sandin: machine. a baee. n flexible channel member-Ito secure the channel member: 10

to the base.

\ RAYMOND A. REID, 

